A Bound and Approximation of Delay Distribution for Fixed-Length Packets in an Unslotted ALOHA Channel and a Comparison with Time Division Multiplexing (TDM)

This paper presents an approximate analysis of a pure unslotted ALOHA random access with fixed-length packets and computes percentiles of delay for various throughputs. It introduces the concept of the burst ratio (mean packet interarrival time/maximum delay) of a source which allows a precise comparison with time division multiplexing (TDM) and indicates when ALOHA is the preferred access technique. The paper presents two curves that should be sufficient for design along with a simple computational procedure. Results are verified and augmented using simulation.